Nearly two in three trafficking victims who are pregnant – many as a result of rape – received no antenatal care before their third trimester, and a third had suicidal thoughts during pregnancy, according to a report by British charity Hestia.

“If you’ve been controlled for most of your life and have lost your sense of agency, then it’s incredibly difficult to trust someone and ask for help,” said Patrick Ryan, chief executive of Hestia, in a phone interview.

Ryan said health professionals needed help to identify trafficking victims, and those women needed priority access to antenatal care, more financial and housing support, and befriending programmes to tackle loneliness.

The report is based on the experiences of more than 140 pregnant women who are or have been victims of trafficking in London - 88 percent were forced into prostitution and one in ten were exploited as maids in people’s homes.

It found that pregnant women did not access health services because they feared reprisals from their traffickers, or because the examinations prompted flashbacks.

In one instance a woman’s first antenatal appointment was so late that she went into labour during her first scan, it said.

Janet Fyle, the Royal College of Midwives’ lead on modern slavery, said pregnant trafficking victims were often “traumatised and in extremely poor physical and mental health, even before they reach Britain”.

“Many are anaemic, have sexually transmitted diseases, wounds or even broken bones as a result of beatings and abuse,” she told the Thomson Reuters Foundation by phone.

Despite repeated efforts, a Home Office spokesman was not available to comment.

Between a quarter and half of trafficking victims in Britain are pregnant or have children with them or in their home countries, according to a 2016 report by the Anti-Trafficking Monitoring Group.

The group’s members include Anti-Slavery International, Amnesty International and the United Nations children’s agency.

At least 13,000 people across Britain are thought to be victims of forced labour, sexual exploitation and domestic servitude, the government has said.

However, the police believe the true figure could be in the tens of thousands with slavery operations on the rise.

Kate Garbers, managing director of Unseen, an anti-slavery charity, said by email that any assistance would also need to help exploited women deal with the impact of sexual assault. (Reporting by Zoe Tabary @zoetabary, Editing by Robert Carmichael. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, property rights, climate change and resilience. Visit news.trust.org)